program factorial;

function factorial(i : integer) : integer;
begin
  if i = 1 then
    factorial := 1
  else
    factorial := factorial(i - 1) * i;
end;

begin
  write('10! = ', factorial(10));
  readln;
end.

{if you want to improve this code, please send code to me
tranleduy1233@gmail.com}